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Best Answer: What's more interesting is WHY 1 isn't considered a prime number.

Yes, it's true to say that the only factors of 1 are 1 and itself, which is why many people incorrectly assume 1 is prime.

The reason why 1 isn't considered prime is really one of convenience - there are plenty of theorems about primes which don't apply to 1. If we considered 1 to be a prime, then all these theorems would read "for all primes except 1..." which would be clumsy.

Example: Every integer greater than one can be factorised into a unique set of primes. E.g. 24 = 2 x 2 x 2 x 3.

If we considered 1 to be a prime, the theorem breaks:
24 = 2 x 2 x 2 x 3 x1, or 2 x 2 x 2 x 3 x 1 x 1, or 2 x 2 x 2 x 3 x 1 x 1 x 1 etc. So we'd have to restate the theorem as "Every integer greater than one can be factorised into a unique set of primes (excluding 1)".

A prime number is any whole number that is strictly greater than 1, whose only two factors are 1 and itself.

1 is not a prime number. Doctor Q and uaris are incorrect.
2 is a prime number. In fact 2 is the only even prime number.

For instance. The number 7. the only two numbers you can multiply to get 7 are (7 times 1). So 7 is prime. But I repeat. 1 IS NOT A PRIME NUMBER. Do not listen to these people that tell you otherwise. Anyone who tells you 1 is a prime number does not know what they are talking about.

First few prime numbers.
2, 3, 5, 7, 11, 13, 17, 19 ...

This link below is the prime number sh*tting bear. Here is a bear that sh*ts prime numbers. Look the first number he sh*ts out is 2.

Prime numbers are numbers that only have 1 and themselves as factors. Three is a prime number because the only numbers that you can divide into three are 3 and 1. Five is a prime number because the only numbers that divide into it are 1 and 5. Two IS a prime number. 1 and 2 are the only numbers that can divide into two. One is NOT a prime number because it's only factor is 1. One divided into one equals one. It has to be 1 and a different number. Hope that helps and doesn't further confuse you. :)

I will give you a very simple answer. Any number which is divisible by itself and not divisible by other numbers except 1 is called a prime number.The number 1 is far more special than prime number,then why is not included as prime number,because of another definition of prime number " Any integer greater than one is called a prime number if its only positive divisors are one and itself ". This clearly shows that 1 is left out, but it does not really the question 'why'. 2 is the prime number. because it is only divisible 1 and by itself.

An alternative, slightly deeper definition of a prime number, is:
p is a prime number <=> p|ab => p|a or p|b, for a natural number p, and integers a, b.

This has the advantage over the conventional definition of a prime number ("only divisible by 1 and itself") in that it allows "prime elements" to be defined in more general number systems (so-called "rings"), with this property holding (with p,a, b now ring elements and p not the zero element).